The present invention relates to an electrical energy distribution systems, and more particularly to a board mounted contactor therefor.
Electrical energy distribution systems typically include an electrical power source which powers a corresponding distribution circuit through a controllable power contactor which selectively interlinks a multitude of distribution circuits. Each distribution circuit is powered by its own source through a corresponding power contactor, however, should a source become defective, the distribution circuit can be powered by the source of at least one other distribution circuit through at least one contactor.
Distribution systems of this type are often utilized onboard aircraft. In this environment, each distribution circuit generally powers a distribution bus bar which then powers a plurality of electrical loads in parallel. Each power source is typically either of a generator driven by an engine of the aircraft, an auxiliary power unit or batteries.
The contactors reside in a power center assembly on a primary bus bar structure located within an aircraft electronics bay. The primary bus bars interface to the contactors through 6 threaded terminal posts, assuming it is a 3 phase, AC contactor. In addition to the primary power interfaces, a low power signal connection is required for control and sensing functions. Because the contactors are line replaceable modules (LRMs) each contactor must have an individual chassis to support a multitude of electrical components and wiring harnesses which connect the LRM to the power center assembly.
The contactors each include an economizer switch to reduce coil currents once closure occurs and a multitude of auxiliary contact switches which indicate the main contact position and who's signals are used for relay logic in the power system. Each of these auxiliary switches are mechanically linked to the contactors primary actuator through a complex set of brackets and adjustment screws. In addition, each of the switches requires a harness to provide the interface to the control and signal connector. During LRM replacement, tooling is required to remove the control and signal connector and large tooling is required to remove fasteners on the primary power interfaces. These interfaces also require a controlled re-torquing procedure and calibrated torque wrench during LRM replacement. Although effective, these features result in a relatively complex LRM that reduces reliability and may result in increased maintenance considerations when located within an aircraft environment.
Accordingly, it is desirable to provide an uncomplicated line replaceable module with a minimum of wire harness connections which reduces maintenance considerations when located within an aircraft environment.